Switch with improved actuator means

ABSTRACT

A switching mechanism that is adapted to be incorporated into a seat to sense the presence of an occupant and actuate a switch in response thereto. The switching mechanism includes a switch supported in a housing and having a movable element with an actuating system cooperating with the switch. The actuating system includes an elongated member having one end connected to the support and a free end spaced from the support. The elongated member extends generally parallel to the upper surface of the seat and is deflected from normal in response to an occupant in the seat. An elongated actuating arm cooperates with the element and the free end of the first elongated member to move the element between the first and second positions in response to deflection of the elongated member thereby actuating the switch. The switching mechanism further includes automatic adjustment means to compensate for manufacturing and age variations of the seat.

United States Patent Gebhardt et al. June 13, 1972 [54] SWITCH WITHIMPROVED ACTUATOR 3,375,495 3/1968 Bums... ..340/278 X MEANS 2,276,3783/1942 Dugvay ..200/l53 V UX [72] Inventors: Wallace A. Gebhardt;Prentice R. Corn, R. Scott both of Logansport, Att0rneyDressler,Goldsmith, Clement & Gordon 73 Assi nee: Switches Incor rated 1 g 57ABSTRACT [22] Filed: March 2, 1971 A switching mechanism that 18 adaptedto be incorporated pp 120,139 into a seat to sense the presence of anoccupant and actuate a switch in response thereto. The switchingmechanism includes 52 U.S. Cl. ..200/52 R, ZOO/61.58 B a suppcinedhavlng a 'f [51] Int Cl "01h 35/00 with an actuating system cooperatingwith the switch. The a.- [58] Field of Search ..200/6l.58 B, 86 R, 86 A,153 v, mating *g g zf gi f 200/527 6L, 61.42, 6143; 307/10; 340/52 278connecte tot e support an a ree en space romt e support. The elongatedmember extends generally parallel to the [56] Refrences Cited uppersurface of the seat and is deflected from normal in response to anoccupant 1n the seat. An elongated actuating UNIT D STATES PATENTS armcooperates with the element and the free end of the first elongatedmember to move the element between the first and 3,109,075 10/1963Ratcliff ..200/52 Second positions in response to d fl ti f theelongated 2,493,157 1/1950 Merralls et a]. ..200/86 R member therebyactuating the switch The Switching 3,297,841 V1967 Campbell B mechanismfurther includes automatic adjustment means to 3,281,818 10/1966 Morganat B X compensate for manufacturing and age variations of the seat.2,996,587 8/1961 McCarthy ..200/6l.58 B 3,166,146 1/1965 Shaw..200/61.58 B X 31 Claims, 16 Drawing Figures I7 I I 8 i wil +1, 4

I *1 24 I as SWITCH WITH IMPROVED ACTUATOR MEANS BACKGROUND OF THEINVENTION The present invention relates generally to switches and morespecifically to an improved seat sensing switch for use as part of awarning system in an automobile.

With the recent emphasis upon safety in the automobile industry and theentry of a federal government into the field for policing safety,numerous safety and warning devices have been incorporated into presentday automobiles. For example, the federal government has recentlyrequired that each new automobile sold must incorporate a sufficientnumber of seat belts to allow at least one seat belt for each occupantof the automobile. While this requirement was readily satisfied by theautomobile industry, one of the problems encountered was the fact thatthe occupants of the vehicle did not use the seat belts in manyinstances thereby negating the possible elimination of injury in anautomobile accident, as was envisioned by the requirement of seat belts.

Thus, the industry and the federal government searched for a solution toat least partially overcome the problem of the occupant neglecting tofasten the seat belt while the automobile is being operated. Thesolution to this problem appeared to the federal authorities asrequiring some type of warning system that would indicate when theoccupant was in the seat and the seat belt was not fastened. In additionto the broad encompassing requirement by the federal government,additional specific requirements were made that must be complied with bythe auto industry. The auto industry in turn made numerous additionalrequirements which had to be met by suppliers of the various elementsthat were needed to comply with the federal regulations.

SUMMARY OF THE INVENTION The present invention contemplates a seatsensing mechanism which includes a switch that will be actuated when theseat is occupied and the occupant fails to fasten the seat belt.

The seat sensing mechanism of the present invention includes a switchhaving a movable element moved between positions to open and close theswitch, which is supported in a housing or support. A switch actuatingmeans moves the element between the positions and includes an elongatedmember or arm connected to the support with a free end spaced from thesupport and being deflected between opposite ends from a normal positionin response to an occupant in the seat. An elongated strap or actuatingarm is connected to the free end of the elongated member and to themovable element to convert the deflection of the elongated member tomovement of the element thereby actuating the switch.

According to one specific aspect of the present invention, frictionclutch means is incorporated in one of the connections to accommodaterelative movement of the connected parts by the subject connection whenthe movement of the actuator arm is greater than the allowable movementof the actuator. In one embodiment, the actuator is interposed betweenthe adjacent end of the actuator arm and the movable element and afriction clutch interconnects the actuator and the actuator arm and actsas yieldable means to accommodate the relative movement between theactuator and the actuator arm. In an alternate embodiment, the frictionclutch is interposed between the opposite end of the actuator arm andthe free end of the elongated member or arm while the remaining end ofthe actuating arm, acting as the actuator, directly engages the movableelement. In both embodiments, the friction clutch automatically causesthe actuating means to compensate for manufacturing variations andchanges induced by use in the contour of the seat.

The switching mechanism further includes first adjustable means forvarying the amount of travel of the element between the open and closedpositions and a further adjustable means for limiting the amount oftravel of the actuator after the movable element is in the closedposition.

In its specific embodiment, the elongated member or tension member forthe elongated strap is in the form of a spring metal strap that isdirectly connected to a main body portion of an elongated resinousspacer that has projections extending from one side thereof. Theprojections cooperate with the elongated strap to maintain the strap andthe elongated member, including the steel strap and the main bodyportion of the resinous spacer in a spaced generally parallel conditionat all times.

The seat sensing mechanism further includes a free or lost motionconnection between the actuator and the movable element to accommodaterelative movement after the element has been moved to its switch closingposition. This significant feature allows for the elongated member to bedeflected an amount greater than necessary for closing of the movableelement and returning to a stable position between the maximum andnormal deflected positions to accommodate increases and decreases inforces on the elongated member while the occupant is in the seat withoutopening the switch.

A further aspect provided by the present invention is an automaticre-adjustment feature to allow for contour variations in manufacturingand changes due to use. The seat sensing mechanism is re-adjusted eachtime the elongated member is deflected an amount greater than necessaryto close the switch. This repositions the actuator causing it to engagethe movable element sooner when the deflecting force is removed. Whenthe seat returns to its static position the actuator will berepositioned to provide original contact adjustment.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF DRAWINGS FIG. 1 is a fragmentaryperspective view of a seat with the switching mechanism of the presentinvention incorporated therein;

FIG. 1a is a schematic illustration of the location of the switchingmechanism in relation to the seat springs;

FIG. 2 is a schematic illustration of an electric circuit incorporatingthe switching mechanism;

FIG. 3 is a fragmentary side elevation view of the switching mechanism;

FIG. 4 is a' fragmentary plan view of the switching mechanism;

FIG. 5 is an enlarged fragmentary sectional view taken along line 5-5 ofFIG. 3;

FIG. 6 is an enlarged fragmentary horizontal sectional view taken alongline 66 of FIG. 5;

FIG. 7 is a plan view, partly in section, of a slightly modified form ofthe switching mechanism;

1 FIG. 8 is a side elevation view of the switching mechanism shown inFIG. 7;

FIG. 9 is an enlarged fragmentary vertical section taken along line 9-9of FIG. 7;

FIG. 10 is a fragmentary section similar to FIG. 9 showing the switch inits actuated position;

FIG. 11 is a sectional view on the scale of FIGS. 7 and 8, and takengenerally along line 1 l-1 I of FIG. 9;

FIG. 12 is a further sectional view on the scale of FIGS. 7 and 8 andsimilar to FIG. 1], taken generally along line 12- 12 of FIG. 9;

FIG. 13 is a fragmentary sectional view taken generally along line 13-13of FIG. 9;

FIG. 14 is a sectional view taken generally along line 14- 14 of FIG.10; and

FIG. 15 is an end view of the actuating means.

DETAILED DESCRIPTION While this invention is susceptible of embodimentin many different forms, there is shown in the drawings and will hereinbe described in detail two specific embodiments, with the understandingthat the present disclosure is to be considered as an exemplification ofthe principles of the invention and is not intended to limit theinvention to the embodiments illustrated.

FIG. 1 of the drawings generally discloses a seat having a back rest' 12cooperating therewith. The seat includes a thickness of compressiblecushioning material that is located between upper and lower surfaces ofthe seat with spring means 14 extending normally front to back acrossthe seat. The spring means 14 (FIG. 1a) is illustrated as a zigzagspring which consists of a wire that is bent to a sinusoidalconfiguration and located in a substantially common horizontal planealong the lower surface of the seat. A pair of seat belt portions 16 areattached to the support for the seat and have buckle portions 18attached to the free ends thereof;

The seat sensing mechanism 20, illustrated in the embodiment of FIGS.3-6, is specifically designed to be supported directly on the uppersurface of the spring 14 and held in a fixed relation thereto, as willbe described later. The sensing or switching mechanism 20 includes aswitch 21 (FIG. 2) having a fixed contact 22 (FIG. 6) and a movablecontact or element 24 that is moved between open and closed or first andsecond positions to actuate the switch. The respective switch contactsare supported in a housing or support 26 and respectively connected toleads or wires 28 that extend out of the housing and are connected in anelectrical circuit 30 that incorporates a second switch 32, a warningdevice 34'and a suitable source of power 36. In the illustratedembodiment, the movable contact or element 24 is formed of a springmetal material that defines biasing means for normally maintaining theelement in the closed position when allowed to close by movement of theactuator 60, to be described later.

Switch actuating means, generally designated as 40, cooperates'with thehousing and the spring biased element or contact 24 to move the contactbetween closed and open positions and actuate the switch in response todeflection of the seat from its normal position. The actuating means isconstructed in accordance with the teachings of the present inventionand is capable of being deflected an amount greater than that requiredfor actuating the switch to compensate for variations in weight of theoccupant as well as variations in forces applied thereto when theoccupant initially occupies the seat or moves to vary the fiexture ofthe actuating means.

The actuating means 40 for moving the element between the two positionsextends from the support in a direction generally parallel to the uppersurface of the seat 10 and terminates in a free end that is spaced fromthe support. The actuating means 40 has sufficient'rigidity to remain ina substantially planar, normal condition when no load or weight issupported on the seat or load supporting device but has sufficientresiliency to be deflected to conform to any normal static seatcondition between its opposite ends or assume anydeflection requiredwhen a load is supported on the seat or device.

The second means or actuator 60 consists of an elongated integral pieceof resinous material that has a transversely extending slot or recess 62adjacent one end thereof. One surface of, the actuator is generally flatand is in contacting engagement with the adjacent surface of theelongated strap 44. According to a primary aspect of the presentinvention, the interconnection between the actuator and the strap 44includes a mechanism or friction clutch for frictionally connecting theactuator to the strap in a manner to accommodate relative movementbetween the actuator and the strap 44 when the strap or elongated member42 has been deflected beyond a predetermined maximum. The mechanism orfriction clutch means 63 is illustrated as including a spring 64 FIG. 5)having one end in engagement with the lower surface of the elongatedstrap 44 and its opposite end in engagement with an enlarged head 66 ofa rivet or other suitable means 68 that extends through an elongatedslot 70 in the strap 44 and has its upper end secured to the actuator60. In connecting the rivet or other suitable securing device 68 to theactuator, the spring 64 is compressed sufficiently toproducea frictionconnection between the strap'and the actuator. The actuator and frictionclutch means define an operative connection between the element 24 andthe actuating arm or strap.

The actuating means, and more specifically the actuator 60, furtherincludes a first portion 72, defined by one side wall of the recess 62,engaging an adjacent surface of the element to hold the element 24 inthe switch open position and allow movement ofthe element to the switchclosed position when the elongated member or resilient arm is moved fromits normal to its deflected position, as will be described later. Theactuator 60 also includes a second'portion 74, between the op- Theactuating means 40 includes a first elongatedsheet metal strap or arm 42that has one end connected to the housing 26 and a free end 43 spacedfrom the housing. The actuating means further includes means or a secondelongated'strap or actuating arm 44 that extends generally parallel tothe first arm and has one end cooperating with the switch element 24 anda free end cooperating with the free end of the first arm or strap 42 toactuate the switch in response to deflection of the straps or armsbetween opposite'ends. Preferably, the straps are maintained in agenerally parallel spaced condition relative to each other, by a spacer48 which includesa substantially continuous portion 50 of a resinousplastic material that is held in direct contacting engagement with themetal strap 42. The spacer 48 'has a plurality of longitudinally spacedspacer means 52 extending from the exposed surface thereof towards theelongated spring metal strap 44.'The free or outer ends of the straps42, 44 and the spacer 48 are held in a fixed relation to each other by arivet 54. The rivet or first means 54 defines an operative connectionbetween the straps at a location spaced from the housing 26 and morespecifically adjacent the free ends of the straps.

The switch actuating means 40 further includes second means or anactuator 60 cooperating with the end of the strap 44 adjacent thehousing to operatively connect the strap to the movable element in amanner which will now be described.

hereinafter.

posite side wall of the recess 62 and the free end of the actuator toprovide a mounting for threaded stud and stop for an adjusting screwv90. The spacing between the respective side walls of the recess isgreater than the thickness of the movable element to define a freemotion connection that accommodates movement between the element and theactuator when the element is in its closed position. The purpose of thefree motion connection will be described According to a further aspectof the invention, the actuator incorporates adjustable means for varyingthe extent of free motion movement between the element and the actuator.This adjustable means is in the form of a screw'80 threaded into anopening in the second portion 74 of the movable plastic actuator 60. Thescrew'or threaded stud 80 extends through an enlarge'd opening 82 in thehousing or support 26 and receives a nut 84 on the outer end thereof.The nut 84 engages the outer surfaces of the housing 26 upon apredetermined amount of movement of the actuator 60 relative to thehousing and prevents further longitudinal movement of the actuator. Theextent of movement of the actuator after the element 24 is in the dottedline position shown in FIG. 6 is set by adjustment of the nut, as willbe described later. i

The actuating means of switch 20 further includes a sensitivityadjustment for varying the sensitivity of the entire device. Thissensitivity adjustment is in the form of a set screw threaded into anopening in the housing or support 26 with the inner end of the set screwor adjustment screw disposed in the path of movement of the actuator 60.The rotation of the screw 90 will determine the extent of travel of theactuator as the switch element 24 is moved between closed and openpositions and can be adjusted to vary the amount of travel of themovable element 24 between its closed and open positions, respectivelyshown by the dotted and solid lines of FIG. 6.

The operation of the sensing mechanism will now be described.Theswitching mechanism 20 is inserted in the seat between the uppersurface of the spring and the lower surface of the cushioning materialwith the wire spring 14 being received in a recess92 defined betweenspaced housing portions 94 and 96. Therernainder of the switchingmechanism consisting of the actuating means or system lies on top of thespring and is held in a position generally parallel to the upper in moredetail surface of the seat by having the cushioning material in directcontact therewith or other suitable means.

In its initial position, the switch actuating means 40, including thetwo straps or arms 42 and 44, and the spacer 48 and the actuator 60 isin a substantially planar normal condition and the movable element orcontact 24 is held in its open position, shown by the solid lineposition of FIG. 6, by cooperative engagement of the first portion 72 ofthe actuator 60 with the element 24. If an occupant should occupy theseat, the weight thereof will cause a compression of the cushioningmaterial and transmit forces in a direction generally perpendicular tothe elongated strap or actuating arm 44, through the strap supportingarm 42 and the spacer 48, to cause the elongated actuating arm 44 todeflect downwardly between its opposite ends. This downward deflectionis converted to linear movement of the actuator 60, through thelongitudinal movement of the adjacent end of the actuating arm 44relative to the support or fixed portion because the outer ends of thestraps and spacer are fixed to each other. By having the lower strap 44spaced below the upper strap 42 and maintained in a generally parallelcondition at all times, through the spacer 48, deflection of the upperstrap from its normal planar condition to a curved configuration willmove the first portion 72 of the actuator away from the contact andallow the biasing means incorporated into the contact or element 24 tomove the element to its closed position.

Once the element or switch contact 24 is in the closed position, it isdesirable to accommodate further movement of the strap or actuating arm44 and actuator 60 a predetermined distance to allow some returndeflection of the actuating means without opening the switch 21. This isdesirable since, when a person initially sits down on the seat, aninitial maximum force will be transmitted to the cushioning material todeflect the cushioning material and the actuating 'means an amountgreater than required for supporting the occupant. After the occupant isseated, the seat and spring will assume an equilibrium condition inwhich the deflection or compression of the cushioning material and thespring 14 is somewhat less than the maximum force or deflectioninitially encountered during the period when the person is sitting down.This variation is absorbed by the free motion connection between theactuator and the element so that the element remains in its closedposition when the equilibrium condition of the cushioning material hasbeen reached. The amount of free travel between the actuator and theelement or contact 24 is set by adjusting the nut 84 relative to thehousing or support 26. In addition, the adjustment screw 90 determinesthe extent of travel of the element 24 between its open solid lineposition and closed dotted line position of FIG. 6 and thereby adjuststhe sensitivity of the switching mechanism.

Assuming that the switching mechanism has just been installed in anautomobile and the sensitivity of the switch and the amount of freetravel between the actuator and the element 24 have been set, the seatsensing mechanism is designed to automatically compensate for a varietyof conditions by incorporation of the friction clutch 63. If a personsits down on the seat, the seat spring 14 will be deflected proportionalto weight applied and deflect the switch actuating means 40 between itsopposite ends into an arcuate configuration. The operative connectionsbetween the arms, the housing, and the element will convert thedeflection or flexing of the arms to produce longitudinal movement ofthe actuating arm relative to the housing or fixed portion. By havingthe elongated strap 44 spaced from the tensioning strap 42 with theinner end guided for movement on the support or housing, the switch willbe actuated with a minimum amount of deflection which will betransmitted through the operative connections to allow the springbiasing of the element 24 to move to a position cor-' responding to theclosed position of the switch. After the switch is in the closedposition, further deflection of the elongated members 42, 44 isaccommodated without movement of the element 24 by the free motionconnection between the actuator 60 and the element 24. After the nut 84engages the outer surface of the support or housing 26, further movementof the actuator is prevented. Thereafter, any further downwarddeflection of the upper strap 42 and consequent downward deflection ofthe lower strap 44 between its opposite ends will overcome thefrictional connection or means in the operative connection between theactuating arm and the actuator, produced by the friction clutch 63between the actuating arm and the actuator to increase the effectivelength of the strap. It should be noted at this point that the biasingforce of the spring 64 must be greater than the biasing force of themovable element 24 in order to accomplish this goal. Stated another way,the friction connection must permit relative movement between theactuator and the actuating arm when the switch is closed and the travelof the adjacent end of the actuating arm in the switch closing directionis greater than the permitted movement of the actuator.

After its initial maximum deflection, the seat 10 and spring 14 willreach an equilibrium condition, in which the two portions 72 and 74 ofthe actuator 60 will, in most instances, be spaced from the contact orelement 24 so that the element is biased and held in its closed positionsolely by the biasing force incorporated therein.

Assuming that the operator then gets off the seat, the inherent tendencyfor-the actuating means 40, including the straps 42, 44 and the spacer48, will tend to return to their flat planar condition. This action isassisted by the tendency for the zigzag spring to also move to itsnormal condition. The flexibility of the switch actuating means 40 willallow it to assume the normal condition of the seat spring 14. Duringsuch movement or return from the deflected to the normal position, thefirst portion 72 of the actuator will engage the movable element 24 andmove theelement from its closed to its open position. After having movedto the open position, defined by the adjustment screw 90, furthermovement of the actuator 60 is prevented. Should the elongated strap 44require further movement to return to its normal position, this movementwill again cause relative movement of the inner end of the strap towardsthe actuator 60 while the actuator remains in its fixed position toautomatically readjust the switch actuating means. It should be noted atthis point, during upward movement of the strap 44 to a normalcondition, the forces produced by the biasing means incorporated intothe element 24 will assist in overcoming the frictional force developedby the spring 64 so that only a minimum amount of additional force needbe developed to produce relative movement between the strap and theactuator.

The self-adjusting feature between the actuator and the strap allows forthe switching mechanism to automatically compensate for permanentchanges in the contour of the seat. For example, assuming that the carhas been in use for some time, the seat spring may have a tendency tosag from its normal condition and remain in a sagged condition withoutany weight being applied or supported on the upper surface thereof. Theswitching mechanism would automatically adjust itself to accommodatesuch changes in configuration of the seat and still remain as sensitiveas it initially was when installed into the automobile. If desired, thefunction of the adjustment nut 84 and reset adjustment screw 80, as wellas set screw 90, could be achieved by proper dimensioning of the lengthof the actuator 60 and the adjacent mating surfaces of the housing 26with this arrangement the opposed inner surfaces of the housing wouldact as fixed stops defining the extent of travel of the actuator.

A slightly modified form of the present invention is disclosed in FIGS.7-15 wherein several of the features described above have been deletedto simplify the construction of the switching means. The switching meansis specifically designed for being incorporated into the cushioningmaterial of the seat adjacent the upper surface thereof.

The switching means or mechanism 100 again includes a switch (FIG. 13)consisting of a fixed contact or element 102 and a movable contact orelement 104 that incorporates biasing means for normally maintaining thecontacts in the closed or second position shown in FIG. 10.

The switch mechanism 100 further includes switch actuating means 106(FIG. consisting of a strap or elongated arm 108 of spring metal and aspacer 110 including a main body portion 112 that is substantiallycoextensive in length and width with the strap 108 and has a pluralityof longitudinally spaced projections 114 extending away from the freesurface thereof. The projections 114 define spacers and some of thespacers have slots or recesses 116 while other of the spacers haveopenings 118. The openings 118 are in'longitudinal alignment with thebottoms of the recesses or slots 116, for-a purpose which will bedescribed later.

In the embodiment illustrated in FIGS. 7-15, the elongated lower strapor actuating arm is in the form of a wire 120 that extends through theopenings 118 and is received into the bottoms of the recesses 116. As inthe previous embodiment, the spacers thus maintain the wire or elongatedstrap 120 in a generally parallel condition to the elongated member atall times. The outer or free end of the wire 120.extends through anopening, 122 in the free end portion 124 of theresinous plastic spacer110. The end of the wire is preferably flattened or, as shown, of has aflat small plate 126 fixedly secured thereto. The end portion of theouter free end 124 of the spacer1l0 has a segment 128 cut away to exposethe lower surface of the plate 126. The operative interconnection isbetween the bowed spring clamp 130 that encompasses the end portion 124and the plate 126 affixed to the spring metal strap or arm 108 that'isreceived into the cutout segment 128 providing frictional engagementbetween elements. In addition, the strap 108 and spacer 110 areinterconnected at the outer or free end by a rivet 132. Thus, the bowedspring clamp 130 provides an operative connection that produces africtional force between the free end of the strap 120 and the ad.-jacent end of the tension member, including strap 108 and spacer 110.The entire actuating means 106 is preferably enclosed in a flexiblesheath or casing 136.

The inner end of the wire 120 is supported for relative movement on thehousing or fixed portion by extending through an opening 140 defined inthe support or housing 150 enclosing the switch and is of sufficientlength to hold the movable element 104 in its open position shown inFIG. 9 when the'actuating means 106 is in a substantially planarcondition. Preferably, the inner end of the wire 120 has an operativeconnection to the element 104 which includes an enlarger bulb oractuator 142 threaded on the free end to produce the butting engagementwith the switch element 104. The bulb 142 is received in a recess orenlarged bore 144, the inner end of which provides an abutment to definethe extent of free travel of the. wire after the switch has been closed.

In the embodiment illustrated in FIGS. 7-15, the adjustable stop 90controlling sensitivity has been replaced by a fixed stop or projection152 which defines the open position for the movable element 104.

It is believed that the description of the operation of the modifiedembodiment need only briefly be summarized since it is substantiallyidentical to the operation of the embodiment previously described.During initial deflection of the actuating means 106, the bulb 142 andthe wire 120 move away from the element 104 and allows the element tomove to its closed position. A predetermined amount of free travel isincorporated into the mechanism after the switch has been closed and isdefined by the position of the bulb 142 and the depth of the bore 144.After the bulb 142 engages the inner endof the bore 144, any furtherdeflection of the actuating means 106 overcomes the friction connectionin the operative connection between the plate 126 and spacer 108,produced by the spring clamp or friction clutch 130, to accommodaterelative movement between the outer ends of the straps 108 and 120.

In both illustrated embodiments, the circuit 30 is defined to give avisual and/or audio signal when the seat is occupied and the occupantfails to place the seat belt around him and fasten the buckle. Theswitch 32 is closed when the seat belt is not buckled while the switch21 is open when the seat is unoccupied so that the switch 21 closes whena person occupies the seat to produce a signal untilfthe seat belt isbuckled around the person. However, various other circuits may beutilized to perform the same function. a

While the metal straps 42, 108 and spacers 48, 110 have been shown asseparate pieces in both embodiments, they could readily be incorporatedinto one piece. For example, the function of the strap 108 could beperformed by the main body portion 112 or the spacer 110. Also, ifdesired, the two arms and spacers could be molded as an integral pieceto maintain a proper spacing between upper and lower continuous portionswhile accommodations relative longitudinal movement or many othercombinations to achieve the same desired action.

Furthermore, while the lower arm has been described as the activatingarm throughout the description, it is recognized that the same functioncan be performed by using the upper arm as the actuating arm while usingthe lower arm as the tension member.

The actuating system for the switch is extremely simple but the uniquearrangement of parts and the operative interconnection between thevarious parts allows the switching mechanism to be initiallyincorporated into the seat and thereafter automatically compensate fornumerous changes in the condition of the seat. The operativeinterconnections automatically accommodate relative movement of certainparts after the switch has been closed and a deflection greater than theswitch closing deflection is applied to the arms in the switch closingdirection.

We claim:

1. In a switching mechanism including a switch having an element movablebetween firstandsecond positions to open and close said switch and ahousing supporting said switch, switch actuating means for moving saidelement and comprising' an elongated arm having a first portioncooperating with said element and a second portion extending away fromsaid housing; an elongated tension member connected to said housing;means maintaining at least a portion of said tension member spaced fromsaid elongated arm; means connecting said tension member to the secondportion of said elongated arm for normally maintaining said arm in asubstantially planar initial condition and deflecting said arm inresponse to forces applied in a direction generally perpendicularthereto to cause said elongated arm to move longitudinally relative tosaid housing, so that said first portion of said elongated arm causessaid element to move to said second position and actuate said switch.

2. A switching mechanism as defined in claim 1,'in combination with aseat having cushioning material between upper and lower surfaces thereofand compressible in response to a load being supported on said uppersurface, said switch actuating means extending generally parallel tosaid upper surface and below said upper surface so that a load onsaidupper surface will deflect the second portion of said elongated armand actuate said switch.

3. The combination as defined in claim 2, in which said element includesbiasing means biasing said element towards said second position and alost motion connection between said element and said elongated arm, saidlost motion connection accommodating independent movement of saidelongated arm when said element is in said second position.

4. The combination as defined in claim 2, further including an actuatoron the first portion of said elongated arm adjacent said element, saidactuator cooperating with said element to define said lost motion;yieldable means defining a friction connection between said actuator andthe first portion of said elongated arm; and means defining a fixedconnection tension member, said yieldable means accommodating relativemovement between said arm and said tension member when said arm isdeflected beyond a predetermined maximum and in which said first portionof said elongated arm is provided at an opposite end of said arm inbutting engagement with said element when said tension member isreturned to the normal position to move said element from said second tosaid first position.

6. A switching mechanism as defined in claim 1 wherein said tensionmember is defined by an elongate strap and an elongate spacer memberlocated between said strap and said elongated arm.

7. A switching mechanism as defined in claim 6 wherein said spacermember maintains said strap in spaced parallel relationship with respectto said elongated arm throughout their respective lengths.

8. A switching mechanism as defined in claim 7 wherein said strap andsaid actuating arm are thin, flat members. I

9. A switching mechanism as defined in claim 1 in which the firstportion of the elongated arm that cooperates with the movable element ofthe switch is an end portion of said arm.

10. In a switching mechanism including a switch having an elementmovable between first and second positions to open and close said switchand a housing supporting said switch, switch actuating means for movingsaid element and comprising an elongated arm having one end cooperatingwith said element and extending away from said housing; and an elongatedtension member connected to said housing and cooperating with saidelongated arm, said tension member normally maintaining said arm in asubstantially planar normal condition and deflecting said arm inresponse to forces applied in a direction generally perpendicularthereto to cause said element to move to said second position andactuate said switch, said elongated arm having first means operativelyconnecting one end thereof to said free end of said tensioning memberand second-means operatively connecting the opposite end of said arm tosaid movable element, one of said first and second means includingyieldable means for accommodating relative movement between connectedparts in response to deflection of said elongated member beyond apredetermined maximum. 1

11. A switching mechanism as defined in claim 10, in which said firstmeans includes a friction clutch frictionally interconnecting the freeend ofsaid tension member and said arm, said friction clutch definingsaid yieldable means.

12. A switching mechanism as defined in claim 10, in which said secondmeans includes an actuator cooperating with said element and saidyieldable means includes a friction clutch frictionally connecting saidactuator to said elongated arm.

13. A switching mechanism as defined in claim 10, in which said secondmeans includes a lost motion connection accommodating relative movementbetween said arm and element when said element is in a second positionand said arm is deflected beyond that required to move said element tosaid second position.

14. A switching mechanism as defined in claim 13, further includingadjustable means for varying the extent of relative movement betweensaid arm and element.

15. A switching mechanism as defined in claim 10, further includingadjustable means cooperating with said element for varying the amount oftravel of said element between said positions to vary the sensitivity ofsaid switch.

16. In a load supporting device having a compressible cushioningmaterial between upper and lower surfaces thereof, a sensing mechanismcooperating with said device and including a switch having an elementmovable between positions to open and close said switch, a support forsaid switch; and actuating means for moving said element between saidpositions, said actuating means comprising: an elongated resilient armconnected to said support, said resilient arm extending from saidsupport in a direction generally parallel to and below said uppersurface of said device; an elongated actuating arm extending generallyparallel to said resilient arm;

means maintaining said arms spaced from one another; a first operativeconnection between one end of said actuating arm and said element formoving said element in response to longitudinal movement of said one endof said actuating arm; and a second operative connection between saidarm at a location spaced from said first operative connection; said armsbeing deflectable between opposite ends in response to a load on saiddevice to cause said actuating arm to move longitudinally relative tosaid support so that the operative connection between said one end ofsaid actuating arm and said element is effective to actuate said switch.

17. A load supporting device as defined in claim 16, in which saidelement includes biasing means normally biasing said element to closesaid switch; and adjustable means cooperating with said actuating meansfor varying the spacing between said open and closed positions to varythe sensitivity of said switch, the further improvement of yieldablemeans in one of said first and second operative connections in responseto deflection of said arms to accommodate relative movement of partsinterconnected by said one of said connections when said switch isclosed and said arms are deflected.

18. A load supporting device as defined in claim 17, in which saidyieldable means includes friction clutch means in said second operativeconnection between said arms; and in which said one end of saidactuating arm engages said element and moves said element between saidpositions to open said switch when said resilient arm is moved from itsdeflected to its normal position, the further improvement of a resilientcasing enclosing said resilient arm and said actuating arm.

19. A load supporting device as defined in claim 17, in which said firstoperative connection includes an actuator between said actuating arm andsaid element with said yieldable means comprising friction clutch meansbetween said actuating arm and said actuator, said actuator having afirst portion engaging said element to move said element from a switchclosing to a switch opening position when said resilient arm is movedfrom its deflected to its normal position, said actuator having a secondportion engaging said element when said resilient arm is moved beyond apredetermined maximum deflected condition to cause relative movementbetween said actuator and said actuating arm and increase the effectivelength of said actuating arm, said portions being arranged to define alost motion connection between said actuator and said element after saidelement is moved to a closed position.

20. A load supporting device as defined in claim 19, further includingan adjustment screw on said support and having a free end disposed inthe path of movement of said actuator, said adjustment screw limitingthe extent of movement of said element to define the sensitivity of saidswitch.

21. A load supporting device as defined in claim 16, further includingspacer means between said arms for maintaining said arms generallyparallel during deflection.

22. An actuating system for a switch mechanism that includes a fixedsupport and a movable element mounted on said fixed support andpositionable in first and second positions to open and close said switchmechanism, comprising: an elongated actuating arm; a supportingconnection between said arm and said fixed support accommodatinglongitudinal movement of said arm; an operative connection between themovable element and the actuating arm for opening and closing saidswitch in response to longitudinal movement of said arm; a further armextending substantially parallel to said actuating arm; a firstconnection between said further arm and said fixed support; a secondconnection between said further arm and said actuating arm, saidconnections and arms cooperating to produce longitudinal movement ofsaid actuating arm relative to said fixed support when a switch closingforce is applied to said arms and means in one of said connections topermit relative movement of parts interconnected by said one of saidconnections when a force is applied to said arms after said switch isclosed.

23. An actuating system as defined in claim 22, in which said operativeconnection includes an actuator cooperating with said element and inwhich said means in one of said connections is a friction Connectionbetween said actuator and said actuating arm; and in which said firstand second connections are fixed connections.

24. An actuating system as defined in claim 22, in which said firstconnection is a fixed connection and said means in one of saidconnections is a friction connection defining said second connectionbetween said arms at a location spaced from said support.

25. A switch comprising: a support, a first contact mounted at a fixedlocation on said support; a second contact carried by said support andmovable toward and away from said first contact; and actuating means forcontrolling movement of said second contact and including a first armsecured to said support and having a portion extending outwardlytherefrom, said first arm being flexible whereby said first arm deflectsfrom a normal position to a deflected position when a force is appliedthereto, said actuating means further including a second arm having acontact moving portion positioned adjacent said second contact, saidsecond arm having a further portion ex-- tending outwardly from saidsupport and connected to said first arm, means maintaining said secondarm in spaced relationship with respect to said first am and supportingsaid second arm for movement longitudinally relative to said first arm,said second arm being flexible whereby said first and second arms form adeflectable unit when a force is applied to said first arm, theconnection between said first and second arms giving said second arm acomponent of motion longitudinally of said first arm and relative tosaid support upon deflection of said unit so that the contact movingportion of said second arm is moved relative to said second contact formovement of said second contact in one direction relative to said firstcontact; and resilient means urging said unit from said deflectedposition to said normal position whereby the contact moving portion ofsaid second arm is moved relative to said second contact for movement ofsaid second contact in a direction opposite to said first direction.

26. A switch as defined in claim 25 wherein said first arm is aninherently resilient member which defines said resilient means.

27. A switch as defined in claim 25 wherein said means maintaining saidfirst arm in spaced relationship with respect to said first arm includesa spacer located between said arms and retaining said arms in spacedparallel relationship with respect to one another throughout theirrespective lengths.

28. A switch as defined in claim 25 wherein said arms are thin, flatstraps.

29. A switching mechanism as defined in claim 10, further includingadjustable means on said housing and located in the path of movement ofsaid second means to vary the sensitivity of said switch.

30. A switching mechanism as defined in claim 12, further includingadjustable means carried by said housing and located in the path ofmovement of said actuator, said adjustable means adjusting the extent oftravel of said actuator after said element is moved from its closedposition.

31. A switch as defined in claim 25, in which said first contact isimmovably mounted on said support.

UHLILJU OLIxLu-J IJLLLJLL \JLL'LuLJ I CERTIFICATE 0F CORRECTION PatentNo. 3, 70,119. Dated June 13,1972

Inventofls) Wallace A. Gebhardt ahd Prentice R. Corn It 1e pertificdthat error appears in the above-identified patent and that seid LettersPatent are, hereby corrected as shown below:

Column 8,-line62, the number "2" should be -3--.

Column 10, line 5-, "arm'" should be ---arms.

; Signed and sealed this 25th day of December 1973.

(SEAL) Attest:

EDWARD M. FLETCHER,JR. RENE D. TEGTMEYER Attesting Officer ActingCommissioner of Patents I" OHM PO- $050 "OJ-5) QERTlFICATE or CORRECTIONPatent No. 34670.119- taxed June 13;, 1972 InventorCs) Wallace A.Gebhardt and Prentice R. Corn It 15 certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

Column 8, line'62, the number "2"- should be -3--.

Column 10, line 5-, "arm'" should be -arms.

;Signed and sealed this 25th day of December 1973.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. RENE D. TEGTMEYER Attesting Officer ActingCommissioner of Patents

1. In a switching mechanism including a switch having an element movablebetween first and second positions to open and close said switch and ahousing supporting said switch, switch actuating means for moving saidelement and comprising an elongated arm having a first portioncooperating with said element and a second portion extending away fromsaid housing; an elongated tension member connected to said housing;means maintaining at least a portion of said tension member spaced fromsaid elongated arm; means connecting said tension member to the secondportion of said elongated arm for normally maintaining said arm in asubstantially planar initial condition and deflecting said arm inresponse to forces applied in a direction generally perpendicularthereto to cause said elongated arm to move longitudinally relative tosaid housing, so that said first portion of said elongated arm causessaid element to move to said second position and actuate said switch. 2.A switching mechanism as defined in claim 1, in combination with a seathaving cushioning material between upper and lower surfaces thereof andcompressible in response to a load being supported on said uppersurface, said switch actuating means extending generally parallel tosaid upper surface and below said upper surface so that a load on saidupper surface will deflect the second portion of said elongated arm andactuate said switch.
 3. The combination as defined in claim 2, in whichsaid element includes biasing means biasing said element towards saidsecond position and a lost motion connection between said element andsaid elongated arm, said lost motion connection accommodatingindependent movement of said elongated arm when said element is in saidsecond position.
 4. The combination as defined in claim 2, furtherincluding an actuator on the first portion of said elongated armadjacent said element, said actuator cooperating with said element todefine said lost motion; yieldable means defining a friction connectionbetween said actuator and the first portion of said elongated arm; andmeans defining a fixed connection between the free end of the secondportion of said elongated arm and said tension member, said yieldablemeans accommodating relative movement between said actuator and said armwhen said arm is deflected beyond a predetermined maximum.
 5. Thecombination as defined in claim 2, further including yieldable meansdefining a friction connection between the free end of the secondportion of said elongated arm and said tension member, said yieldablemeans accommodating relative movement between said arm and said tensionmember when said arm is deflected beyond a predetermined maximum and inwhich said first portion of said elongated arm is provided at anopposite end of said arm in butting engagement with said element whensaid tension member is returned to the normal position to move saidelement from said second to said first position.
 6. A switchingmechanism as defined in claim 1 wherein said tension member is definedby an elongate strap and an elongate spacer member located between saidstrap and said elongated arm.
 7. A switching mechanism as defined inclaim 6 wherein said spacer member maintains said strap in spacedparallel relationship with respect to said elongated arm throughouttheir respective lengths.
 8. A switching mechAnism as defined in claim 7wherein said strap and said actuating arm are thin, flat members.
 9. Aswitching mechanism as defined in claim 1 in which the first portion ofthe elongated arm that cooperates with the movable element of the switchis an end portion of said arm.
 10. In a switching mechanism including aswitch having an element movable between first and second positions toopen and close said switch and a housing supporting said switch, switchactuating means for moving said element and comprising an elongated armhaving one end cooperating with said element and extending away fromsaid housing; and an elongated tension member connected to said housingand cooperating with said elongated arm, said tension member normallymaintaining said arm in a substantially planar normal condition anddeflecting said arm in response to forces applied in a directiongenerally perpendicular thereto to cause said element to move to saidsecond position and actuate said switch, said elongated arm having firstmeans operatively connecting one end thereof to said free end of saidtensioning member and second means operatively connecting the oppositeend of said arm to said movable element, one of said first and secondmeans including yieldable means for accommodating relative movementbetween connected parts in response to deflection of said elongatedmember beyond a predetermined maximum.
 11. A switching mechanism asdefined in claim 10, in which said first means includes a frictionclutch frictionally interconnecting the free end of said tension memberand said arm, said friction clutch defining said yieldable means.
 12. Aswitching mechanism as defined in claim 10, in which said second meansincludes an actuator cooperating with said element and said yieldablemeans includes a friction clutch frictionally connecting said actuatorto said elongated arm.
 13. A switching mechanism as defined in claim 10,in which said second means includes a lost motion connectionaccommodating relative movement between said arm and element when saidelement is in a second position and said arm is deflected beyond thatrequired to move said element to said second position.
 14. A switchingmechanism as defined in claim 13, further including adjustable means forvarying the extent of relative movement between said arm and element.15. A switching mechanism as defined in claim 10, further includingadjustable means cooperating with said element for varying the amount oftravel of said element between said positions to vary the sensitivity ofsaid switch.
 16. In a load supporting device having a compressiblecushioning material between upper and lower surfaces thereof, a sensingmechanism cooperating with said device and including a switch having anelement movable between positions to open and close said switch, asupport for said switch; and actuating means for moving said elementbetween said positions, said actuating means comprising: an elongatedresilient arm connected to said support, said resilient arm extendingfrom said support in a direction generally parallel to and below saidupper surface of said device; an elongated actuating arm extendinggenerally parallel to said resilient arm; means maintaining said armsspaced from one another; a first operative connection between one end ofsaid actuating arm and said element for moving said element in responseto longitudinal movement of said one end of said actuating arm; and asecond operative connection between said arm at a location spaced fromsaid first operative connection; said arms being deflectable betweenopposite ends in response to a load on said device to cause saidactuating arm to move longitudinally relative to said support so thatthe operative connection between said one end of said actuating arm andsaid element is effective to actuate said switch.
 17. A load supportingdevice as defined in claim 16, in which said element includes biasingmeans normally biasing said element to close said sWitch; and adjustablemeans cooperating with said actuating means for varying the spacingbetween said open and closed positions to vary the sensitivity of saidswitch, the further improvement of yieldable means in one of said firstand second operative connections in response to deflection of said armsto accommodate relative movement of parts interconnected by said one ofsaid connections when said switch is closed and said arms are deflected.18. A load supporting device as defined in claim 17, in which saidyieldable means includes friction clutch means in said second operativeconnection between said arms; and in which said one end of saidactuating arm engages said element and moves said element between saidpositions to open said switch when said resilient arm is moved from itsdeflected to its normal position, the further improvement of a resilientcasing enclosing said resilient arm and said actuating arm.
 19. A loadsupporting device as defined in claim 17, in which said first operativeconnection includes an actuator between said actuating arm and saidelement with said yieldable means comprising friction clutch meansbetween said actuating arm and said actuator, said actuator having afirst portion engaging said element to move said element from a switchclosing to a switch opening position when said resilient arm is movedfrom its deflected to its normal position, said actuator having a secondportion engaging said element when said resilient arm is moved beyond apredetermined maximum deflected condition to cause relative movementbetween said actuator and said actuating arm and increase the effectivelength of said actuating arm, said portions being arranged to define alost motion connection between said actuator and said element after saidelement is moved to a closed position.
 20. A load supporting device asdefined in claim 19, further including an adjustment screw on saidsupport and having a free end disposed in the path of movement of saidactuator, said adjustment screw limiting the extent of movement of saidelement to define the sensitivity of said switch.
 21. A load supportingdevice as defined in claim 16, further including spacer means betweensaid arms for maintaining said arms generally parallel duringdeflection.
 22. An actuating system for a switch mechanism that includesa fixed support and a movable element mounted on said fixed support andpositionable in first and second positions to open and close said switchmechanism, comprising: an elongated actuating arm; a supportingconnection between said arm and said fixed support accommodatinglongitudinal movement of said arm; an operative connection between themovable element and the actuating arm for opening and closing saidswitch in response to longitudinal movement of said arm; a further armextending substantially parallel to said actuating arm; a firstconnection between said further arm and said fixed support; a secondconnection between said further arm and said actuating arm, saidconnections and arms cooperating to produce longitudinal movement ofsaid actuating arm relative to said fixed support when a switch closingforce is applied to said arms and means in one of said connections topermit relative movement of parts interconnected by said one of saidconnections when a force is applied to said arms after said switch isclosed.
 23. An actuating system as defined in claim 22, in which saidoperative connection includes an actuator cooperating with said elementand in which said means in one of said connections is a frictionconnection between said actuator and said actuating arm; and in whichsaid first and second connections are fixed connections.
 24. Anactuating system as defined in claim 22, in which said first connectionis a fixed connection and said means in one of said connections is afriction connection defining said second connection between said arms ata location spaced from said support.
 25. A switch comprising: a support,a first contacT mounted at a fixed location on said support; a secondcontact carried by said support and movable toward and away from saidfirst contact; and actuating means for controlling movement of saidsecond contact and including a first arm secured to said support andhaving a portion extending outwardly therefrom, said first arm beingflexible whereby said first arm deflects from a normal position to adeflected position when a force is applied thereto, said actuating meansfurther including a second arm having a contact moving portionpositioned adjacent said second contact, said second arm having afurther portion extending outwardly from said support and connected tosaid first arm, means maintaining said second arm in spaced relationshipwith respect to said first arm and supporting said second arm formovement longitudinally relative to said first arm, said second armbeing flexible whereby said first and second arms form a deflectableunit when a force is applied to said first arm, the connection betweensaid first and second arms giving said second arm a component of motionlongitudinally of said first arm and relative to said support upondeflection of said unit so that the contact moving portion of saidsecond arm is moved relative to said second contact for movement of saidsecond contact in one direction relative to said first contact; andresilient means urging said unit from said deflected position to saidnormal position whereby the contact moving portion of said second arm ismoved relative to said second contact for movement of said secondcontact in a direction opposite to said first direction.
 26. A switch asdefined in claim 25 wherein said first arm is an inherently resilientmember which defines said resilient means.
 27. A switch as defined inclaim 25 wherein said means maintaining said first arm in spacedrelationship with respect to said first arm includes a spacer locatedbetween said arms and retaining said arms in spaced parallelrelationship with respect to one another throughout their respectivelengths.
 28. A switch as defined in claim 25 wherein said arms are thin,flat straps.
 29. A switching mechanism as defined in claim 10, furtherincluding adjustable means on said housing and located in the path ofmovement of said second means to vary the sensitivity of said switch.30. A switching mechanism as defined in claim 12, further includingadjustable means carried by said housing and located in the path ofmovement of said actuator, said adjustable means adjusting the extent oftravel of said actuator after said element is moved from its closedposition.
 31. A switch as defined in claim 25, in which said firstcontact is immovably mounted on said support.